1. In collaboration with Drs. Morell and Friedman of the SHG, our audiology unit has used a battery of tests of central auditory and speech processing in a large cohort of monozygotic and dizygotic twins in order to test the hypothesis that one or more measurable parameters of these phenomena are heritable, They have determined that performance on at least one of the tests shows a very high heritability. This particular trait may be amenable to molecular genetic approaches to identify the genes underlying the observed variation. 2. In collaboration with Dr. Drayna of the Laboratory of Molecular Genetics, our audiology unit is using a battery of audiologic tests to detect auditory physiologic abnormalities associated with tune deafness. They have identified at least one test in which performance is strongly correlated with tune deafness. 3. In collaboration with Drs. Hallett and Garvey of the NINDS, the audiology unit has been involved in the design, implementation, and data analysis for two different safety studies on the auditory system (and hearing) after exposure to transcranial magnetic stimulation (TMS) in adults and children, respectively. TMS is a widely utilized clinical neurophysiologic technique whose effects on hearing have not been adequately characterized for many of the devices, or for children. 4. In collaboration with Dr. Al Braun and others, the audiology unit is involved in the design, implementation, and data analysis of safety studies on the auditory system (and hearing) after exposure to either multiple MRI scans, or MRI scans performed in new scanners. 5. The Hearing Section conducts the auditory phenotypic assessment of individuals with hearing loss and enlarged vestibular aqueducts (EVA), as well as their siblings and parents. About 90 probands and their families have now been ascertained, and the audiologic data reveals a correlation of the auditory phenotype with the underlying SLC26A4 (PDS) genotype. The audiology unit is currently evaluating details of the auditory phenotype to search for features that predict genotype, clinical prognosis, or clinical diagnosis. 6. In collaboration with investigators from other NIH institutes, we continue to evaluate hearing and balance manifestations in Von Hippel-Landau disease (Dr. Linehan, NCI), Turner syndrome (Dr. Bondy, NICHD), Fanconi anemia and other inherited bone marrow failure syndromes (Dr. Alter), neonatal onset multi-system inflammatory disorder (Dr. Goldbach-Mansky, NIAMS), familial cold urticaria/MuckleWells syndrome (Dr. Goldbach-Mansky, NIAMS), Fabry disease (Dr. Schiffman, NINDS), Pallister-Hall syndrome (Dr. Biesecker, NHGRI), Smith-Magenis syndrome (Ms. Smith, NHGRI), Usher syndrome (Dr. Sieving, NEI), xeroderma pigmentosum (Dr. Kraemer, NCI), progeria (Dr. Gordon, NHGRI), McCune-Albright syndrome and Polyostotic Fibrous Dysplasia (Dr. Collins, NIDCR), and anthrax (Dr. Wright, NIAID). 7. The Audiology Unit has characterized the clinical phenotype of eight affected members of a large family segregating autosomal dominant, nonsyndromic, postlingual-onset, progressive sensorineural hearing loss caused by a mutation of the EYA4 gene at the DFNA10 locus. 8. In collaboration with Dr. Leopold (NIMH), the audiology unit is involved in the design, implementation, an analysis of safety studies on the auditory system in macaque monkeys exposed to functional MRI noise.